Effect of pretreatment of barley seedlings with different salts on the level of UV-B induced and UV-B absorbing compounds

• Published in: Environmental and experimental botany Vol. 56; no. 3; pp. 225 - 230
• Main Authors: Fedina, Ivanka, Georgieva, Katya, Velitchkova, Maya, Grigorova, Irena
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-07-2006; Elsevier Science
• Subjects: barley; Biological and medical sciences; chemical constituents of plants; chlorophyll; Chlorophyll fluorescence; electron transfer; Flavonoids; fluorescence; Fundamental and applied biological sciences. Psychology; gas production (biological); Hordeum vulgare; hydrogen peroxide; malondialdehyde; oxygen; Oxygen evolution; photosynthesis; Plant physiology and development; potassium chloride; pretreatment; proline; radiation injury; radiation resistance; Salt stress; seedlings; sodium chloride; sodium nitrate; ultraviolet radiation; ultraviolet-B absorbing compounds; ultraviolet-B induced compounds; UV-B absorbing compounds; UV-B induced compounds; Water and solutes. Absorption, translocation and permeability; maximal fluorescence of PSII in dark-adapted state; Salt stress; UV-B induced compounds; Hordeum vulgare; chlorophyll fluorescence of dark-adapted state; Chl; chlorophyll; photochemical quenching; MDA,malondialdehyde; Chlorophyll fluorescence; UV-B absorbing compounds; photosynthetic photon flux density; Flavonoids; F m; TCA; non-photochemical fluorescence quenching; F 0; trichloracetic acid; Oxygen evolution; variable chlorophyll fluorescence; PPFD; F v; qN; qP; Chlorophyll; Monocotyledones; UVB radiation; Tolerance; Stress; Salinity; Gramineae; Angiospermae; Spermatophyta; Pretreatment
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/j.envexpbot.2005.02.006

The relationship between the level of UV-B-induced and/or UV-B-absorbing compounds and stress tolerance of barley seedlings
(Hordeum vulgare L. cv. Alfa) was investigated. A physiological response to UV-B irradiation was evaluated by measuring the oxygen evolution rate and chlorophyll fluorescence. UV-B irradiation led to an increase of the amount of UV-B absorbing compounds, including flavonoids, measured in acidified methanol extract at 300
nm and of UV-B induced compounds, with maximum absorbance at 438
nm, extracted in 0.1% trichloracetic acid. The content of free proline, malondialdehide and H
2O
2 increased as a result of 4 days treatment with 150
mM NaCl, KCl or NaNO
3. Salt pretreatment resulted in considerable decrease of the level of UV-induced and UV-B absorbing compounds measured 24
h after UV-B irradiation. In the meantime chlorophyll fluorescence parameters and oxygen evolution in salt pretreated seedlings were less affected by UV-B in comparison to the control. Damaging effect of UV-B measured by the MDA and H
2O
2 generation and electron transport activity corresponded to the increased levels of UV-B induced and UV-B absorbing compounds. We do not necessarily exclude UV-inducing compounds from an important role in overall UV-B protection but the data presented here showed that the accumulation of these compounds could be a consequence of stress-induced damage to the cells and probably they may serve as stress markers.